The revoke perms might work - I just hate fooling with perms they intimidate me.

We have an auction forum where members donate items for an auction to fund the site. But the guys who run it have a 2 week period where they accept items befroe the auction starts. However the rule is no bidding until the auction starts. So as it stands, when donor posts a thread, between the time a moderator sees it to close iit, usually several new members who haven't read the rules start bidding right away before the thread is closed.